For the past several years, there has been a significant amount of effort directed to converting biomass to fuels and other useful chemicals. This is due in large part to the rising cost of crude oil, motivating researchers to seek alternative sources of hydrocarbons.
A chemical processing technique that has long been used to convert biomass into a useful product is called fast, or rapid, pyrolysis. Rapid pyrolysis is the thermal decomposition of carbonaceous material or biomass, over just a few seconds, in the absence of oxygen to produce char, pyrolysis oil, and non-condensing gases (NCGs). Pyrolysis oil derived from plant material such as wood, is a complex mixture of hydrocarbons, oxygenated compounds, and water.
Unfortunately, this kind of pyrolysis oil is not miscible with any conventional hydrocarbon based fuels unless it is further treated in a process called “upgrading.” The upgrading process involves contacting the pyrolysis oil with hydrogen, under pressure and heat, to de-oxygenize, de-carboxylate, and de-water it. Only after it is upgraded may it then be further processed into conventional hydrocarbon fuels.
Logically, any energy or cost efficiencies provided by using pyrolysis oil is reduced by the amount of energy and time required to process the pyrolysis oil before it can be used. Accordingly, it would be beneficial to be able to skip the upgrading process.
One solution to this problem is to make the pyrolysis oil soluble in hydrocarbon based fuel by creating an emulsion, which involves adding a chemical called an emulsifier. While emulsifying the mixture is useful, it is still not ideal as it involves adding chemicals into the mixture that may interfere with its use.